This has been my experience-- I don't check Amazon and stop for almost anything at this point because I often find computer hardware might be cheaper elsewhere. Newegg is hit and miss but sometimes comes out way ahead-- I saved $100 on a monitor by going Newegg instead of Amazon, even after shipping.

Groceries? I find that Amazon almost never wins there compared to the local grocery chain. That most certainly is going to end up being a "where you are right now" kind of thing compared to computer parts.